Ms Han has served on WuXi's board since 2008. WuXi is now looking for a new board member to replace Ms Han.

"I am very grateful to have had the opportunity to serve on the board of a great company like WuXi since 2008," said Ms Han. "I have seen the tremendous growth and success of WuXi, and will continue to be a supporter of WuXi's vision to enable anyone and any company to develop healthcare products to benefit patients."

Dr Ge Li, chairman and CEO, WuXi PharmaTech, commented, "On behalf of the board, I want to thank Ying for her many years of excellent service as a WuXi board member. All of us at WuXi wish her the very best."